https://github.com/w3c/csswg-drafts/commit/c10855a2c65f51a09697613b977059fae78ff0bc
<rdar://problem/83530242>
Created attachment 439271 [details] Patch
This patch modifies the imported WPT tests. Please ensure that any changes on the tests (not coming from a WPT import) are exported to WPT. Please see https://trac.webkit.org/wiki/WPTExportProcess
I think the GTK errors are spurious. It looks like they're not regenerating the derived sources from the .idl change.
Created attachment 439436 [details] Patch
Created attachment 439444 [details] Patch
Created attachment 439520 [details] Patch
Committed r283219 (242261@main): <https://commits.webkit.org/242261@main>